The present invention relates to a condenser mainly utilized in an air-conditioning system for vehicles, which is constituted by providing a liquid tank next to a header pipe and connecting the liquid tank to the header pipe via a connecting block.
A condenser is normally connected to a coolant piping by securing a connecting block to a header pipe of the condenser and bonding an end of the coolant piping to the connecting block. For instance, as disclosed in Japanese Unexamined Patent Publication No. H 10-141888, a communicating hole 12 is formed at a connecting block 8, a hole 4a is formed at a header pipe 4 as well and the header pipe and the connecting blocked are bonded to each other through furnace brazing with the communicating hole 12 and the hole 4a aligned with each other.
In addition, if a liquid tank is provided next to either one of the header pipes, a structure illustrated in FIG. 8, for instance, may be assumed by bonding the liquid tank to the header pipe via a connecting block. In this example, numerous flat tubes 2 are inserted at a header pipe 1 over appropriate intervals and a partitioning plate 3 for partitioning the header pipe 1 is provided at an appropriate position in the header pipe 1. Holes 4 and 5 are formed on opposite sides of brazing the partitioning plate 3 at the header pipe 1. It is to be noted that the surface of the header pipe 1 is clad with a brazing material.
At a connecting block 6, an intake-side communicating passage 7 and an outlet-side communicating passage 8 are formed, connecting stages (for housing O-rings for sealing) 7a and 8a of the communicating passages 7 and 8 are formed on the front side, the rear side of the connecting block 6 is formed as a straight surface, the communicating passages 7 and 8 are aligned with the holes 4 and 5 of the header pipe 1 and the brazing material on the surface of the header pipe melts to weld the connecting block 6 to the header pipe 1 during the furnace brazing process.
However, while the connecting block 6 is welded onto the header pipe 1, the brazing material melting from the surface of the header pipe 1 enters the communicating passages 7 and 8 via the brazing surface to reach the connecting stages 7a and 8a which are not brazing surfaces to lower the surface accuracy of the connecting stages 7a and 8a. As a result, the sealing function achieved through the O-rings is compromised to cause a coolant leak.
Accordingly, an object of the present invention is to ensure that the sealing function achieved at the connecting stages is not compromised by preventing the brazing material at the surface of the header pipe from entering the communicating passages for coolant intake/outlet at the connecting block during the furnace brazing process.
In the condenser according to the present invention having a liquid tank, which is also provided with a header pipe at least on one side with the liquid tank set next to the header pipe, a connecting block utilized to connect the liquid tank is provided with a pair of communicating passages for coolant intake/outlet, pipe-like projections are formed at the communicating passages on the side where the connecting block is connected to the header pipe and the connecting block is welded to the header pipe with the pipe-like projections inserted at holes formed at the header pipe clad with a brazing material, and the pipe-like projections are located between flat tubes inserted and fixed to the header pipes.
Thus, since the pipe-like projections at the connecting block utilized to connect the liquid tank are projected between the flat tubes inserted and fixed to the header pipes, the brazing material at the surface of the header pipe is not allowed to enter the communicating passages even when it melts, to ensure that the sealing function achieved at the connecting stages is not compromised, and even if the pipe-like projections are inserted into the header pipes and project inside thereof, they can avoid interfering with the flat tubes.
In addition, the pitch of the pipe-like projections at the pair of communicating passages formed at the connecting block is an integral multiple of the pitch of the flat tubes inserted at and connected to the header pipe.
Furthermore, the pipe-like projections at the communicating passages of the connecting block are loosely inserted at the holes formed at the header pipe. Alternatively, the pipe-like projections at the communicating passages of the communicating block may be fitted inside the holes formed at the header pipe through press fitting.
As described above, the pipe-like projections are loosely inserted at the holes formed at the header pipe with a clearance or they are fitted inside the holes formed at the header pipe through press fitting by setting the diameter of the holes at the header pipe almost equal to the external diameter of the pipe-like projections. In the latter case, a temporary retention of the connecting block to the header pipe which must be achieved prior to the brazing process is realized.
The distance over which the pipe-like projections at the communicating passages of the connecting block project out is set larger than the wall thickness of the header pipe. Since this allows the pipe-like projections to project out into the header pipe, the melted brazing material cannot enter the communicating passages.
Note that while the shape of the pipe-like projections at the communicating passages of the communicating block normally have a circular section, they may be formed to have a flat section to be used in conjunction with flat tubes set over smaller intervals (smaller pitch).